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Ground loop issues from computer audio

B

Bouly

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Oct 22, 2021
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Hello, I am looking for advice on how to solve ground loop issues on my home computer setup. The main thing is that I want to be able to quickly switch between a desktop computer and a laptop for the audio source. Here is a schematic of the setup :

Capture d’écran 2021-10-22 à 11.34.53.png

I am considering replacing the power strip with a filtered one such as https://www.av-connection.com/?PGr=13568 .
Would that be a solution?
I thought plugging all components in the same power strip would solve ground loop issues, but I still have the ground loop.
Thanks for any insight.
 
What's the symptom of your ground loop, ie what are you hearing?

Have you tried a cheater plug on the active speakers?
 
If you lift the ground of your PC that will solve the issue but it is somewhat hazardous so generally it is not advisable...
I have done that in the past when I had a miniDSP DAC8 and it worked like a charm

A more acceptable solution could be to use an isolation transformer on your mains: https://www.radioparts.com.au/produ...ectrostatic-screen-mains-electrostatic-screen
I am using one of those now and there is no more noise and the audio quality also got better since the isolation transformer provides galvanic isolation from your mains (=mains noise will not get through due to the lack of metallic connection)
 
raindance said:
What's the symptom of your ground loop, ie what are you hearing?

Have you tried a cheater plug on the active speakers?
Click to expand...
Buzzing when moving the mouse. Noise whenever the computer is processing something.
 
Bouly said:
Hello, I am looking for advice on how to solve ground loop issues on my home computer setup. The main thing is that I want to be able to quickly switch between a desktop computer and a laptop for the audio source. Here is a schematic of the setup :

View attachment 160689
I am considering replacing the power strip with a filtered one such as https://www.av-connection.com/?PGr=13568 .
Would that be a solution?
I thought plugging all components in the same power strip would solve ground loop issues, but I still have the ground loop.
Thanks for any insight.
Click to expand...

Same strip is no help. Put an isolation transformer before the PC, as I draw in the picture.

loopin system.png


isol_tr.JPG


I use
BREVE TUFVASSONS
PFS250/230/230V

www.welectron.com

Breve-Tufvassons PFS250/230/230V Trenntransformator 230V, 250VA, 99,0

Portabler Sicherheits- und Trenntransformator mit Schuko-Stecker und Steckdose, 230 VAC, IP44, Schutzklasse II, zur galvanischen Potentialtrennung
www.welectron.com www.welectron.com
or if 250VA is not enough, go to higher VA rating.
 
Bouly said:
Ok so I just made some tests. The issue seems to be coming from the external GPU. When I plug it out of the MacBook the ground loop disappears.
Click to expand...

Then put the isolation transformer before the MacBook. It may help or it will help before the PC, somewhere the loop is to be interrupted.
 
JayGilb said:
A good quality audio isolation transformer between your passive source switch and the powered speakers would probably be the easiest fix.
Low quality audio isolation transformer tend to roll off lower frequencies.

Jensen makes quality transformers. Link: Line Level Isolation Transformer
Click to expand...

They are more expensive than the mains line isolation transformer and they degrade audio signal, especially at low frequencies. I am leaving the thread, there will be no help.
 
raindance said:
That is not a ground loop. It's interference and it's probably the laptop power supply.
Click to expand...
How would you solve interference then ? what's the difference with the ground loop ? I thought ground loop was causing interference
 
Bouly said:
How would you solve interference then ? what's the difference with the ground loop ? I thought ground loop was causing interference
Click to expand...
Optical isolation works, balanced connections works, also sometimes using a different power supply helps. There's a lot of trial and error in figuring this out. But a ground loop is typically a constant hum.
 
Alright so I have ordered 2 items :
- a high end ground separator : http://www.jenving.com/products/view/ags-10k-audio-4xrca-1021000045 . I would place it right after the audio source selector.
- a smart power filter : https://ifi-audio.com/products/gnd-defender/ . I would place it before the desktop computer or before the external GPU power supply.
When these items arrive, I will test them, and report if they fixed the issue. I picked these because I can install them with minimal changes to my current setup. If I still have the issue I will switch to an external DAC that can have 2 USB sources (to connect it to both the laptop and desktop) and has XLR output.
 
Bouly said:
Ok so I just made some tests. The issue seems to be coming from the external GPU. When I plug it out of the MacBook the ground loop disappears.
Click to expand...
How much does it drowe, did you try to put it on another wall plug?

Edit: I know Asus can be itchy.
 
Bouly said:
Alright so I have ordered 2 items :
- a high end ground separator : http://www.jenving.com/products/view/ags-10k-audio-4xrca-1021000045 . I would place it right after the audio source selector.
- a smart power filter : https://ifi-audio.com/products/gnd-defender/ . I would place it before the desktop computer or before the external GPU power supply.
When these items arrive, I will test them, and report if they fixed the issue. I picked these because I can install them with minimal changes to my current setup. If I still have the issue I will switch to an external DAC that can have 2 USB sources (to connect it to both the laptop and desktop) and has XLR output.
Click to expand...
That audio isolation transformer is interesting in that the L and R outputs are mirrored from the inputs. Something to watch out for when connecting. The technical specs are incomplete; it has a frequency range of 10-22k, but no +-db specs are given.

Good luck and I hope all is fixed when these devices are installed. I wouldn't worry too much about low frequency loss when using this isolation transformer.



ags-10k_600_v2.jpg
 
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